Later this year, Turkey will host the 2015 G-20 Leaders’ Summit, the 10th annual meeting of the G-20 heads of government. The country’s prominence on the world stage comes at an odd time, when it finds itself surrounded by a widening arc of instability.

Indeed, two geopolitical orders are unraveling in Turkey’s immediate neighborhood: The post-Cold War entente with Russia, and the national borders in the Middle East defined by the 1916 Sykes-Picot Agreement and 1919 Treaty of Versailles. Never have the European Union and Turkey needed one another more, and yet rarely have they been so distant.

Turkey is no longer the rising regional star that it was during the first half of President Recep Tayyip Erdogan’s 12 years in office. Long gone are the days when the country was booming economically and advancing toward true democracy, a source of inspiration to many in the region. Today, Turkey faces myriad challenges: Growing authoritarianism, unimpressive growth and a faltering Kurdish peace process. With a 900-kilometer border with Syria, it is hosting nearly two million Syrian refugees and is vulnerable to attacks and infiltration by the Islamic State. Tensions with both Iran and Israel have become deeply entrenched and the country has become increasingly dependent on energy from a revanchist Russia.

Turkey cannot confront these challenges alone. The EU accounts for almost 40 percent of Turkish trade, 70 percent of its foreign direct investment, and more than 50 percent of its tourism industry. Meanwhile, the country’s economic ties with its southern neighbors have spiraled downward since the Arab Spring in 2011.

This reality is reflected in Turkish public opinion, with support for the EU rising from a low of 34 percent in 2009 to53 percent last year. Simply put, Turkey is waking up to the reality that it has no attractive alternative to the EU and close cooperation with the transatlantic community. The country’s « EU Strategy » announced by European Affairs Minister Volkan Bozkir last fall can be read as an implicit recognition of this fact.

Meanwhile, Europe has never had a greater interest in a stable, democratic, and western-oriented Turkey. Without Turkey’s cooperation, Europe and the international community will struggle to confront the threat of foreign fighters, defeat the Islamic State, stabilize Iraq and craft a political solution to the Syrian quagmire. The EU also needs a sound partnership with Turkey to achieve energy security through diversification.

And yet, rather than being drawn closer together, the EU and Turkey are drifting apart. Freedom of expression, the separation of powers and the rule of law have been progressively eroded under Erdogan. The country risks being sucked into the region’s sectarian conflicts – and being tempted by the authoritarian sirens of Vladimir Putin’s Russia.

The EU-Turkey relationship hit a new low at the close of last year, when Turkey increased its pressure on media close to the self-exiled Islamic leader Fethullah Gulen. The clampdown triggered strong criticism by the EU, which Erdogan, in turn, angrily rejected.

Some in Europe argue that the deterioration of rights and freedoms in Turkey is so serious that the already-moribund EU accession process should be suspended. Indeed, it would be difficult to make the case that Turkey fulfills the Copenhagen political criteria. For example, Turkey slid in Reporters Without Borders’ World Press Freedom Index to 154th place (out of 180 countries). But it is unlikely that a formal suspension of accession negotiations would do anything other than remove the last incentive for Turkey to pursue democratization and EU harmonization. Instead, the EU should redouble its efforts, strengthening both its criticism of Turkey’s democratic backsliding and the credibility of its accession process.

Until now, Cyprus has posed the biggest obstacle to Turkish accession. EU member states should engage more actively with the Cypriot government to bring about the necessary change. This would enable the EU to open chapters 23 and 24 of the accession talks – those that deal with rights, fundamental freedoms, and the judiciary – as the European Parliament and the European Commission advocate. The EU would then be able to cast its criticism within the appropriate legal framework, while Turkish leaders would no longer be in a position to brush aside the EU’s concerns.

Lifting its blockade on negotiations would benefit Cyprus as much as Europe. No country would gain more than Cyprus from stable democracy in Turkey, whereas a de-democratizing Turkey in an unraveling neighborhood seriously threatens Cypriot and European interests alike.

Beyond the EU accession process, other important measures should be taken to rebuild trust and deliver concrete benefits to both sides, thereby revitalizing an ailing and yet increasingly strategic relationship. Such steps should include deepening EU-Turkey cooperation on counter-terrorism, Syrian refugees, and the multiple crises from Libya to Ukraine, as well as upgrading and modernizing the customs union agreement (as the World Bank recently advocated) and vigorously pursuing visa liberalization.

Though these measures are not alternatives to a revamped accession process, they would help to revive it. Above all, by embedding Turkey within the European family, such measures would counter the country’s dangerous drift away from our common European values.

* Martti Ahtisaari, a former president of Finland and Nobel Peace Prize laureate, is a member of the Independent Commission on Turkey. Emma Bonino, a founding member of the European Council on Foreign Relations, is former Italian Minister of Foreign Affairs and the founder of the international NGO No Peace Without Justice. Albert Rohan, a former Secretary General of Austria’s foreign ministry, was deputy UN Special Envoy for the final status negotiations for Kosovo.